Steerable endoluminal punch

ABSTRACT

A transseptal punch with a steering mechanism within the punch, such that punch can be steered and deflected within a guide catheter during delivery, to avoid skiving of the guide catheter inner wall by passage of the punch tip through the guide catheter. The punch can be advanced through a body lumen in its straight configuration and then be selectively articulated or curved to permit negotiation of tortuous curvature or to permit optimal approach or access to a puncture site. The punch is able to create holes in the atrial septum of the heart or other structures and is easier to use than punches that are pre-curved near their distal tip since it is easier to advance through accessory catheters.

This application is a continuation of U.S. application Ser. No.13/944,448, filed Jul. 17, 2013, now U.S. Pat. No. 9,445,836, which is acontinuation of U.S. application Ser. No. 12/785,309, filed May 21,2010, now U.S. Pat. No. 8,491,619, which is a continuation of U.S.application Ser. No. 11/492,328, filed Jul. 24, 2006, which in turnclaims priority benefit under 35 USC §119(e) to U.S. ProvisionalApplication No. 60/702,239, filed Jul. 25, 2005, the entire contents ofwhich are hereby incorporated herein by reference.

FIELD OF THE INVENTION

The invention relates to devices and methods for performing endovascularaccess to the cardiovascular system or other body vessels or bodylumens, especially procedures performed in the fields of cardiology,radiology, electrophysiology, and surgery.

BACKGROUND OF THE INVENTION

During certain interventional procedures that are directed at cardiacaccess, the patient is catheterized through an access point in a vein orartery. A catheter is routed to the heart or other region of thecardiovascular system through the access point, which may be created bya cutdown or a percutaneous access procedure. The catheter may be routedto a target location within the heart, cerebrovasculature, or otherregion of the cardiovascular system. In certain cases, it becomesnecessary to create a hole in a cardiovascular structure so thatcatheters or devices can be routed through a wall so as to provide forplacement on the other side of the wall. One such case is the need topunch a hole in the septum that divides the right atrium of the heartfrom the left atrium. Such atrial septal punctures are increasingly usedto gain access to the left atrium by way of the central venous systemand the right atrium. Access to the left atrium of the heart is oftenuseful in therapeutic and diagnostic procedures such as, but not limitedto, valve replacement, valve repair, electrophysiology mapping, cardiacablation, atrial appendage plug placement, and the like.

The currently accepted procedure for left atrial access involves routinga needle called a Brockenbrough™ needle into the right atrium with theBrockenbrough needle pre-placed within a guiding catheter. The guidingcatheter specifically preferred for use with a Brockenbrough needle iscalled a Mullins™ catheter. The Brockenbrough needle is a long punchformed from a stainless steel wire stylet that is surrounded by astainless steel tube. The distal end of the stainless steel tube forms arelatively sharp circular punch capable of penetrating certain vascularstructures such as the inter-atrial septum. Brockenbrough needle styletsare typically 0.013 to 0.014 inches in diameter while the stainlesssteel tube is generally between 0.045 and 0.050 inches in outsidediameter. The Brockenbrough needle outside diameter is configured toslidingly fit within the central lumen of the Mullins catheter. Thestainless steel tube is substantially straight along most of its lengthbut is pre-bent into a curved or “J” shape at its distal end. A loop atthe proximal end of the Brockenbrough stylet facilitates grasping of thestylet and performing manual advance or retraction. The current artconsiders the access to the right atrium from the femoral vein to berelatively straight so the current devices are straight except for thedistal curve, which is shaped for the approach to the atrial septalwall.

The Brockenbrough needle, a relatively rigid structure, is operated byadvancing the device, with its stylet wire advanced to blunt the sharptip, within its guiding catheter through the inferior vena cava and intothe superior vena cava. Under fluoroscopic guidance, the Brockenbroughneedle, retracted inside the distal tip of the Mullins catheter, iswithdrawn caudally into the right atrium until it falls or translatesmedially into the Fossa Ovalis. The force of the Brockenbroughneedle/Mullins catheter assembly pushing against the relatively weakatrial septal wall causes the Fossa Ovalis to become tented toward theleft atrium. The Brockenbrough needle, protected by the blunt distal tipof the Mullins catheter, is firmly held against the Fossa Ovalis of theatrial septum. Pressure monitoring and dye injection are carried outthrough the central lumen of the punch following removal of the styletwire. The circular or hollow punch is next advanced distally to puncturea hole through the atrial septum. Erroneous placement of the punch canlead to penetration of adjacent structures such as the aorta, damage towhich would cause potentially severe hemorrhage and potentiallycompromise the health of the patient. Thus, extreme care is exercised toverify location prior to the actual punching step. The Brockenbroughneedle is next advanced through the atrial septum. The guide catheter,which includes a removable, tapered, distal dilator, having a centrallumen for the Brockenbrough needle, is advanced over the Brockenbroughneedle system and into the left atrium. The Brockenbrough needle is nextremoved from the Mullins guide catheter along with the central dilatoror obturator.

A main disadvantage of this system is that the Brockenbrough needlesystem is pre-curved at its distal end and is relatively rigid. Thispre-curving, rigidity, and necessary distal sharpness causes theBrockenbrough needle system to carve material from the interior wall ofthe otherwise straight guiding catheter when the Brockenbrough needleassembly is inserted therethrough. The material carved from the guidecatheter could potentially be released into the cardiovascular systemand generate emboli with any number of serious clinical sequelae. Shouldthis embolic catheter material enter the left atrium it could flow intoand block important arterial vasculature such as the coronary arteriesor cerebrovasculature. Furthermore, advancing a pre-curved, rigid punchthrough the cardiovascular system is difficult and could potentiallydamage the vessel wall or any number of significant cardiovascularstructures, during the advancement.

It would be desirable to have a Brockenbrough needle system that wasinitially straight and then became curved after being inserted into theguiding catheter. Such a straight Brockenbrough configuration would beadvantageous during ex-vivo insertion as well as insertion after theguide catheter has already been placed into the cardiovascular system.During ex-vivo insertion, the debris can be flushed from the lumen ofthe guide catheter but complete removal is not assured and emboli canstill be generated by the device. However, if the guide catheter wasalready inserted into the cardiovascular system, the debris could not beflushed out ahead of time and could easily flow toward or be releasedinto the cardiovascular system with potentially catastrophic or fatalresults. Furthermore, the needle or punch could be more easily advancedinto the body lumen if it were not pre-curved.

SUMMARY OF THE INVENTIONS

In an embodiment, the invention is a transvascularly or endovascularlyplaced tissue punch, with internal deflectability or the ability toarticulate, at its distal end, in a direction away from its longitudinalaxis. The punch can also be termed a catheter, needle, or cannula. Thepunch is generally fabricated from stainless steel and comprises anouter tube, an intermediate tube, a central stylet wire, and a distalarticulating region. The deflecting or articulating mechanism isintegral to the punch. The punch, needle, or catheter is sufficientlyrigid, in an embodiment, that it can be used as an internal guidewire orinternal guide catheter. The punch is useful for animals, includingmammals and human patients and is routed through body lumens or otherbody structures to reach its target destination.

In an embodiment, the punch comprises an inner core wire or stylet, anintermediate tube and an outer tube. In an embodiment, the stylet can beremovable or non-removable. The punch further comprises a hub at itsproximal end which permits grasping of the punch and also includes astopcock or valve to serve as a lock for the stylet, or inner core wire,as well as a valve for control of fluid passage into and out from theinnermost lumen within which the stylet or inner core wire resides. Theproximal end further comprises one or more control handles to manipulatethe amount of articulation at the distal end of the catheter. Theproximal end further is terminated with a female Luer or Luer lock port,which is suitable for attachment of pressure monitoring lines, dyeinjection lines, vacuum lines, a combination thereof, or the like.

The punch is fabricated so that it is substantially straight from itsproximal end to its distal end. Manipulation of a control mechanism atthe proximal end of the punch causes a distal region of the punch tobend or curve away from its longitudinal axis. The bending, steering, orarticulating region is located near the distal end of the punch and canbe a flexible region or structure placed under tension or compression bypull wires or control rods routed from the control handle at theproximal end of the punch to a point distal to the flexible region. Inanother embodiment, the bending or articulating mechanism can also becreated by pre-bending the outer tube in one direction and bending theintermediate tube in another direction. The two tubes can be rotatedrelative to each other, about their longitudinal axis, by turning knobsor grips at the proximal end of the punch. When the curvatures of bothtubes are aligned, the tubes will generally cooperate and not opposeeach other, thus, maximum curvature or deflection is generated. When thetubes are rotated so their natural curvatures are aligned 180 degreesfrom each other, the curves will oppose each other or cancel out. Thus,the nested tubes will be substantially straight when the curvatures ofthe two concentric tubes oppose each other. Alignment marks orgraduations at the proximal end can be used to assist with properrotational alignment of the two tubes. The central core wire or styletis generally straight and flexible and does not contribute to thecurvature. In another embodiment, however, the stylet can be impartedwith a curvature to assist with steering or articulation. Rotation ofthe two concentric tubes at relative angles between 180 degrees and 0degrees will result in intermediate amounts of deflection so the amountof deflection can be increased or decreased in an analog, continuouslyvariable, digital, or stepwise fashion. The stepwise or digital responsecan be generated using detents or interlocks that weakly engage atspecific pre-determined locations. A locking mechanism can be furtherutilized to hold the two tubes in rotational alignment once the desiredamount of curvature has been achieved.

In another embodiment, steerability can be obtained using actuators onthe surface or within the interior of the cannula to force bending ofthe cannula. These actuators can be typically electrically powered. Inan embodiment, an actuator can comprise electrical leads, a powersource, a compressible substrate, and shape memory materials such asnitinol. Such actuators may be distributed along the length of thecannula. The actuators may be placed so as to oppose each other.Opposing actuators are activated one at a time and not simultaneouslyand can generate a steering effect or back and forth motion.

Other embodiments of the inventions comprise methods of use. One methodof use involves inserting the central core wire so that it protrude outthe distal end of the punch. A percutaneous or cutdown procedure isperformed to gain access to the vasculature, either a vein or an artery.An introducer and guidewire are placed within the vasculature and theguidewire is routed proximate to the target treatment site. Theintroducer can be removed at this time. A guiding catheter, preferablywith a central obturator or dilator is routed over the guidewire to thetarget site. In an embodiment, the target site can be the atrial septum.The guidewire can be removed at this time. The punch is adjusted so thatit assumes a substantially straight configuration. The punch can beadvanced through the central lumen of the already placed catheter. Bymaking the punch as straight as possible, there is no curvature to forcethe sharpened distal edges of the punch to scrape the inside of thecatheter lumen as the punch is advanced distally inside the guidecatheter and potentially dislodge or scythe away debris or materialwhich could cause embolic effects to the patient. Carefully ensuringthat the punch does not protrude beyond the distal end of the catheteror its obturator, the punch is next deflected so that it forms a curve.The curve is oriented so that it is medially directed toward the atrialseptum. Alignment with any curvature of the catheter can be completed atthis time. The punch and guide catheter/obturator are withdrawncaudally, as a unit, into the right atrium. The punch and guide catheterare positioned using fluoroscopy or other imaging system against theFossa Ovalis. The Fossa Ovalis is a relatively thin structure and theforce of the punch will tent the Fossa Ovalis toward the left atrium. Inone embodiment, the central core wire or stylet, initially advanced, cannext be withdrawn to expose the sharp distal edge of the punch. Whencorrectly positioned under fluoroscopy, ultrasound, or other imagingsystem, dye can be injected into the central lumen of the punch at itsproximal end and be expelled out of the distal end of the punch andobturator to paint or mark the Fossa Ovalis. A generally “V-shaped” markcan be observed under fluoroscopy, which denotes the location of theFossa Ovalis. The curvature of the punch can be increased or decreasedby articulation to gain optimal alignment with the Fossa Ovalis. Thissteering function can be very beneficial in device placement.

Maintaining the position of the guiding catheter against the FossaOvalis, the punch is advanced distally against and through the atrialseptum, in the region of the Fossa Ovalis, so that it penetrates andprotrudes into the left atrium. In order to stabilize the atrial septaltissue prior to coring, a distally protruding corkscrew tipped wire or avacuum head operably connected to the proximal end of the punch, can beused to grasp and retract the septal tissue. Once the initialpenetration is completed, the guide catheter is next advanced, with itstapered obturator leading the way, across the atrial septum until itresides within the left atrium. The tapered obturator or dilator alongwith the punch can be removed at this time to allow for catheterplacement through the guiding catheter. In another embodiment, acalibrated spacer can be used between the guide catheter hub and thepunch hub to ensure that the punch does not protrude beyond the distalend of the guide catheter tip until the desired time for punching thehole. At this point, the spacer is unlocked and removed from the punchor catheter.

In another embodiment, the core wire or stylet is sharpened and servesas a tissue punch. In this embodiment, the distal end of the hollowtubes of the punch are blunted and made relatively atraumatic. Once thecore wire punch has completed tissue penetration, the outer tubes areadvanced over the central punch wire through the penetration and intothe left atrium. In another embodiment, a pressure monitoring devicesuch as a catheter tip pressure transducer, or a pressure lineterminated by a pressure transducer, can be affixed to a quick connect,generally a Luer fitting, at the proximal end of the punch hub. Bymonitoring pressure, it is possible to determine when the distal end ofthe punch has passed from, for example, the right atrium into the leftatrium, because the pressure versus time curves in these two chambersare measurably, or visually, different. The proximal end of the hubfurther has provision for attachment to a dye injection line for use ininjecting radiographic contrast media through the central lumen of thepunch. Typically a manifold can be attached to the Luer fitting on theproximal end of the hub, the manifold allowing for pressure monitoring,for example on a straight through port, and for radiopaque dyeinjection, for example through a side port. A stopcock, or other valve,can be used to control which port is operably connected to the centrallumen of the punch.

For purposes of summarizing the invention, certain aspects, advantagesand novel features of the invention are described herein. It is to beunderstood that not necessarily all such advantages may be achieved inaccordance with any particular embodiment of the invention. Thus, forexample, those skilled in the art will recognize that the invention maybe embodied or carried out in a manner that achieves one advantage orgroup of advantages as taught herein without necessarily achieving otheradvantages as may be taught or suggested herein. These and other objectsand advantages of the present invention will be more apparent from thefollowing description taken in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

A general architecture that implements the various features of theinvention will now be described with reference to the drawings. Thedrawings and the associated descriptions are provided to illustrateembodiments of the invention and not to limit the scope of theinvention. Throughout the drawings, reference numbers are re-used toindicate correspondence between referenced elements.

FIG. 1 illustrates a side view of a trans-septal punch assembled so thatthe intermediate tube is bent in a direction 180 degrees opposite thatof the outer tube, resulting in a substantially straight punchconfiguration;

FIG. 2 illustrates a side view of the disassembled trans-septal punchshowing the central core wire or stylet, the intermediate tube bent inone direction and the outer tube bent in another direction;

FIG. 3 illustrates a side view of the trans-septal punch assembled sothat the intermediate tube bend is aligned in the same direction as theouter tube bend, resulting in a curved distal end on the punch assembly;

FIG. 4 illustrates a side view of a trans-septal punch comprising aflexible region proximal to the distal end and pull-wires disposedbetween the distal end and the proximal end of the punch;

FIG. 5 illustrates a side view of the trans-septal punch of FIG. 4wherein one of the pull-wires is placed in tension causing the distalflexible region of the punch to deflect into an arc away from thelongitudinal axis of the punch;

FIG. 6 illustrates an adjustable, spacer, which sets and maintains thedistance between the distal end of the punch hub and the proximal end ofa guide catheter hub.

DETAILED DESCRIPTION OF THE INVENTION

In accordance with current terminology pertaining to medical devices,the proximal direction will be that direction on the device that isfurthest from the patient and closest to the user, while the distaldirection is that direction closest to the patient and furthest from theuser. These directions are applied along the longitudinal axis of thedevice, which is generally an axially elongate structure having one ormore lumens or channels extending through the proximal end to the distalend and running substantially the entire length of the device.

FIG. 1 illustrates a side view of a punch, needle, or catheter assembly100, with an integral articulating or bending mechanism. The punchassembly 100 comprises a stylet or obturator wire 102, an intermediatetube 104, an outer tube 106, an obturator grasping tab 108, a stopcock110, an intermediate tube pointer 112, an outer tube pointer 114, anintermediate tube hub 116, and an outer tube hub 118.

Referring to FIG. 1, the obturator wire 102 is affixed to the obturatorgrasping tab 108. The stylet or obturator wire 102 is inserted throughthe central lumen of the intermediate tube 104 and is slidably disposedtherein. The stopcock 110 is affixed to the intermediate tube hub 116and the through lumen of the stopcock 110 is operably connected to thecentral lumen of the intermediate tube 104. The intermediate tubepointer 112 is affixed to the intermediate tube hub so that it isvisible to the user. The outer tube pointer 114 is affixed to the outertube hub 118 so that it is visible to the user. The intermediate tubehub 116 and the intermediate tube 104 are able to rotate about thelongitudinal axis within the outer tube hub 118 and the outer tube 106.In an embodiment, the intermediate tube 104 is restrained fromlongitudinal motion relative to the outer tube 106. In anotherembodiment, the intermediate tube 104 can be advanced distally relativeto the outer tube 106. In this latter embodiment, advancement of theinner tube 104 can be used to facilitate punching. The distal end of theintermediate tube 104 can be sharpened and serve as a punch. The distalend of the intermediate tube 104 is sheathed inside the outer tube 106to protect the tissue from the sharp distal edge of the intermediatetube 104 until the intermediate tube 104 is advanced distally outsidethe distal end of the outer tube 106. A releaseable lock can be used tomaintain the axial or longitudinal position of the intermediate tube 104relative to the outer tube 106 until punching is required. A releaseablelock can further be used to maintain the rotational position of theintermediate tube hub 116 and thus the intermediate tube 104 relative tothe outer tube hub 118 and the outer tube 106.

All components of the punch assembly 100 can be fabricated from metalssuch as, but not limited to, stainless steel, Elgiloy™, cobalt nickelalloy, titanium, nitinol, or the like. The nitinol can be shape-memoryor it can be superelastic. The metals used in the obturator wire 102,the intermediate tube 104 and the outer tube 106 are advantageously coldrolled, heat treated, or otherwise processed to provide a full springhardness. The intermediate tube 104, the outer tube 106, or both, arerelatively rigid, resilient structures. Polymeric materials, such as,but not limited to, polycarbonate, ABS, PVC, polysulfone, PET,polyamide, polyimide, and the like, can also be used to fabricate thestopcock 110, the intermediate tube hub 116, the outer tube hub 118, theintermediate tube pointer 112, and the outer tube pointer 114. Thematerials are beneficially radiopaque to maximize visibility underfluoroscopy during the procedure. Additional radiopaque markersfabricated from tantalum, platinum, iridium, barium sulfate, and thelike can be added to improve visibility if needed. The intermediate tube104 is curved or bent near its distal end into a gentle curve,preferably with a radius of between 1 to 5 inches and so that the distaltip is deflected through an angle of approximately 10 to 90 degrees fromthe longitudinal axis of the intermediate tube 104. The outer tube 106is curved or bent near its distal end into a gentle curve, preferablywith a radius of between 1 to 5 inches and so that the distal tip isdeflected through an angle of approximately 10 to 90 degrees from thelongitudinal axis of the outer tube 106. The intermediate tube hub 116is welded, silver soldered, bonded, crimped, or otherwise fastened tothe proximal end of the intermediate tube 104 so that the intermediatetube pointer 112 points in the direction of the bend in the intermediatetube 104. The outer tube hub 118 is welded, silver soldered, bonded,crimped, or otherwise fastened to the proximal end of the outer tube 106so that the outer tube pointer 114 points in the direction of the bendin the outer tube 106. When the intermediate tube pointer 112 isoriented 180 degrees away from the direction of the outer tube pointer114, the bend in the intermediate tube 104 substantially counteracts oropposes the bend of the outer tube 106 and the coaxial assembly 100 issubstantially straight, as shown in FIG. 1. The stopcock 110 can also bea ring seal, Tuohy-Borst valve, membrane valve, hemostasis valve, gatevalve, or other valve, generally, but not necessarily manually operated.The stiffness of the intermediate tube 104 and the outer tube 106 aresufficient that the punch can be used as a guide for other cathetersthrough which the punch 100 is passed.

FIG. 2 illustrates a side view of a stylet or obturator 140 furthercomprising the obturator wire 102 and the obturator-grasping tab 108.The obturator wire 102 is blunted at its distal end to render it asatraumatic as possible. In another embodiment, the obturator wire 102can be tapered in diameter to render it very flexible and thereforeatraumatic at its distal end. The obturator wire 102, in anotherembodiment, can be sharpened and serve as a needle or primary punchingmechanism. FIG. 2 also illustrates an intermediate punch assembly 120further comprising the intermediate tube 104, the stopcock 110, theintermediate tube pointer 112, the intermediate tube hub 116, anintermediate tube seal 124, an intermediate tube pointer ball 126, athrough lumen port 128, a beveled distal tip 132, and a pre-set curve136. FIG. 2 further illustrates an outer tube assembly 122 furthercomprising the outer tube 106, the outer tube hub 118, the outer tubepointer 114, an outer tube distal curve 130, and an outer tube pointerball 134.

Referring to FIG. 2, the obturator-grasping tab 108 is affixed, eitherintegral to, silver soldered, welded, crimped, adhered, pinned, orotherwise attached, to the proximal end of the obturator wire 102. Theintermediate tube 104 is affixed to the intermediate tube hub 116 bysilver soldering, welding, potting, crimping, setscrew, pin, or otherfixation method, such that the hub 116 rotates 1 to 1 with theintermediate tube 104. An optional intermediate tube pointer ball 126 isaffixed to the intermediate tube pointer 112 and provides additionalvisual and tactile rotational positioning sense for the intermediatepunch or needle assembly 120. A curve or bend 136 is heat set, or coldworked into the intermediate tube 104 at or near its distal end. Thedistal end of the intermediate tube 104 comprises a bevel 132 whichhelps serve as a punch or cutting edge for the intermediate tube 104.The angle of the bevel 132 can range between 20 and 70 degrees from thedirection perpendicular to the longitudinal axis of the intermediatetube 104. In another embodiment, the bevel is removed and the distal tipof the intermediate tube 104 is a gentle inward taper or fairing movingdistally that serves as a dilator should the obturator wire 102 be usedas the punching device rather than the blunt distal tip obturator of theintermediate tube 104. The intermediate tube hub 116 further comprises acircumferential groove with an “O” ring 124 affixed thereto. The “O”ring 124 serves to form a fluid (e.g. air, blood, water) tight seal withthe inner diameter of the outer sheath hub 118 central lumen and allowsfor circumferential rotation of the intermediate tube hub 116 within theouter tube hub 118. The “O” ring 124 is fabricated from rubber, siliconeelastomer, thermoplastic elastomer, polyurethane, or the like and may belubricated with silicone oil or similar materials. The stopcock 110 canbe a single way or a three-way stopcock without or with a sideport,respectively.

The outer punch assembly 122 comprises the bend 130, which is heat setor cold worked into the outer tube 106 in the same longitudinal locationas the bend 136 of the intermediate tube. The wall thicknesses of theintermediate tubing 104 and the outer tubing 106 are chosen to providebending forces that cancel out when the curves 136 and 130 are orientedin opposite directions and the intermediate tubing 104 is inserted fullyinto the outer tubing 106. The wall thickness of the outer tube 106 andthe intermediate tube 104 can range between 0.003 inches and 0.20inches, preferably ranging between 0.004 and 0.010 inches. The outerdiameter of the outer tube 106 can range between 0.014 and 0.060 inchesand preferably between 0.025 and 0.050 inches. The outer diameter of theobturator wire 102 can range between 0.005 and 0.030 inches andpreferably range between 0.010 and 0.020 inches.

FIG. 3 illustrates a side view of the punch assembly 100 fully assembledand aligned so that both the intermediate tube distal curve 136 (Referto FIG. 2) and the outer tube distal curve 130 are aligned in the samedirection resulting in a natural bend out of the axis of the punch 100.The punch assembly 100 comprises the obturator wire 102, theintermediate tube 104, the outer tube 106, the obturator grasping tab108, the stopcock 110, the intermediate tube pointer 112, the outer tubepointer 114, the intermediate tube hub 116, the intermediate tubepointer ball 126, and the outer tube pointer ball 134.

Referring to FIG. 3, the outer tube pointer 114 and intermediate tubepointer 112 are aligned together and in this configuration, the tubingassembly possesses its maximum curvature, which is oriented in the samedirections as the pointers 112 and 114. The pointer balls 126 and 134are aligned together to provide additional tactile and visual indices ofcurvature direction. In an embodiment, the curvature of the tubeassembly 104 and 106 is unbiased with no net force exerted therebetweenand an angle of approximately 45 degrees is subtended by the device inthe illustrated configuration. Further curvature can also occur out ofthe plane of the page so that the curvature takes on a 3-dimensionalshape, somewhat similar to a corkscrew. In another embodiment, thecurvature of the aligned inner tube 104 and the outer tube 106 subtendsan angle of 90-degrees or greater. Again, the intermediate tube 104 andthe outer tube 106 have stiffness sufficient that the assembly iscapable of guiding any catheter through which the punch 100 is passed.In another embodiment, the intermediate tube 104 and the outer tube 106have different degrees of curvature so that when they are aligned, a netforce still is generated between the two tubes, although a maximumcurvature configuration is still generated. This embodiment can beadvantageous in permitting articulation in a direction away from thedirection of primary curvature. The radius of curvature of the punch 100can range from substantially infinity, when straight, to as little as0.5-cm, with a preferred range of infinity to as little as 2-cm radiuswhen fully curved or articulated. One embodiment permits a substantiallyinfinite to a 3-cm radius of curvature. The overall working length ofthe punch, that length from the proximal end of the outer tube hub tothe distal most end of the punch, can range from 10 to 150-cm andpreferably between 60 and 100-cm, with a most preferred range of between70 and 90-cm. A preferred curve has a radius of about 3-cm and is bentinto an arc of about 45 to 90 degrees.

FIG. 4 illustrates a side view of another embodiment of a needle orpunch assembly 400 comprising an obturator wire 102, an obturator wiregrasping tab 108, a stopcock 110, an intermediate tube 404, an outertube 406, a plurality of deflecting wires 412, an outer tube hub 414, adeflecting lever 416, a weld 420, an axis cylinder 424, a plurality ofdeflecting wire channels 426, and a flexible region 430. The distal endof the region just proximal to the flexible region 430 is shown inbreakaway view. Furthermore, the distal end of the region just proximalto the flexible region 430 as well as the flexible region 430 has beenexpanded in scale so that certain details are more clearly visible.

Referring to FIG. 4, the flexible region 430 is affixed to the outertube 406 by a weld 420. The flexible region 430 can also be fixed to theouter tube 406 by a crimp, pin, setscrew, adhesive bond, interferencefit, mechanical interlock, thread, or the like. The attachment betweenthe flexible region 430 and the outer tube 406 is made at the proximalend of the flexible region 430 and a second attachment or weld 420 canbe made at the distal end of the flexible region 430 so as to attach toa length of distal outer tube 406. The flexible region 430 can comprisea length of coiled wire such as that used in guidewires, it can be atube that comprises cutouts to provide a backbone configuration toimpart flexibility, it can be a length of polymeric tube withelastomeric characteristics, or it can be another type of structure thatis known in the art as providing flexibility. These preferred structuresalso advantageously provide column strength and kink resistance to theflexible region 430. The center of the flexible region 430 is hollow andcomprises a lumen, which is operably connected to the central lumen ofthe outer tube 406 at both the proximal and distal end of the flexibleregion 430. The stopcock 110 is affixed, at its distal end, to the outertube hub 414. The outer tube hub 414 further comprises a deflectinglever 416 that is affixed to the axis cylinder 424, which serves as anaxle or rotational pin, and can be moved proximally or distally bymanual action on the part of the operator or by a motor or otherelectromechanical actuator (not shown). The deflecting lever 416 isoperably connected to the proximal ends of the deflecting wires 412. Inan exemplary embodiment, one of the deflecting wires 412 is affixed tothe top of the axis cylinder 424 and the other deflecting wire isaffixed to the bottom of the axis cylinder 424. When the deflectinglever is pulled proximally, for example, the top wire 412 is placedunder tension and the tension on the bottom wire is relieved causingtension to be exerted on the distal end of the punch 400. The deflectingwires 412 are slidably routed through the deflecting wire channels 420within the outer tube 406. The deflecting wires 412 also run through thedeflecting wire channels 420 within the flexible region 430. Thedeflecting wires 412 can also be routed through the internal lumen ofthe outer tube 406 and the flexible region 430.

Referring to FIG. 4, the outer tube hub 414 is affixed to the proximalend of the outer tube 406 by a crimp, pin, setscrew, adhesive bond,interference fit, mechanical interlock, thread, or the like. Theintermediate tube 404 is affixed to the distal end of the outer tube 406by a crimp, pin, setscrew, adhesive bond, interference fit, mechanicalinterlock, thread, or the like. In another embodiment, the intermediatetube 404 is routed throughout the length of the outer tube 406. In thisembodiment, the intermediate tube can comprise grooves (not shown) thatserve as deflecting wire channels 420 when the intermediate tube 404 isinserted inside the outer tube 406. Such grooves can also be disposed onthe interior surface of the outer tube 406, rather than on the exteriorsurface of the inner tube 404. The obturator wire 102 and the attachedgrasping loop 108 are slidably disposed within the inner lumen of theouter tube 406, or the intermediate tube 404. The intermediate tube 404is gently tapered up to the outer tube 406 at the distal end of theouter tube 406 in a transition region so that a dilator effect can becreated during distal advancement of the punch 400. The distal end ofthe intermediate tube 404 can comprise a bevel 132 (FIG. 2) or othersharp point for punching through biological tissue. The distal end ofthe intermediate tube 404 preferably forms a non-coring needle or punchthat does not excise a tissue sample. The non-coring punch feature isachieved by keeping the central lumen closed or very small. Thenon-coring punch 400 embodiment can comprise filling the lumen of theintermediate tube 404 with the obturator or stylet wire 102 to preventthe sharp edge of the intermediate tube from functioning as a trephine.

FIG. 5 illustrates a side view of the punch assembly 400 wherein thedeflecting lever 416 has been withdrawn proximally causing increasedtension in one of the deflecting wires 412, causing the flexible region430 to bend 422 out of the longitudinal axis. The punch assembly 400further comprises the obturator wire 102, the obturator wire graspingtab 108, the stopcock 110, the deflecting lever 416, an axis cylinder424, the hub 414, the outer tubing 406, the intermediate tubing 404, andthe bend 422.

Referring to FIG. 5, the deflecting lever 416 has been moved proximallyand the axis cylinder 424 causing the top deflecting wire 412 to beplaced in tension while the bottom deflecting wire 412 is relaxed. Thedeflecting wires 412 are affixed at their distal end to the outer tubing406 or the intermediate tubing 404 at a point substantially at or beyondthe distal end of the flexible region 420. The distal fixation point(not shown) of the deflecting wires 412 is off-center from the axis ofthe outer tubing 406 or intermediate tubing 404. When uneven tension iscreated in the opposing deflecting wires 412, the uneven tension on thedistal end of the punch 400 causes the bendable region 430 to undergodeflection into a curve or bend 422. Similarly, forward movement of thedeflecting lever 416 will place the bottom deflecting wire 412 intension while the upper deflecting wire 412 will be relaxed, causing thepunch 400 to undergo a bend in the opposite direction (downward). Thedeflecting lever 416 can further comprise a ratchet and lock, a frictionlock, a spring-loaded return, or other features to hold position orcause the lever and the bendable region 430 to return to a neutraldeflection configuration (substantially straight). The spring nature ofthe outer tube 406 and the bendable region 430 can advantageously beused to cause a return to neutral once the deflection force is removedfrom the deflecting lever 416. The stylet or obturator wire 102 can bewithdrawn or extended to expose or protect (respectively) the distal endof the intermediate tube 404 which can be sharpened or blunted. Theobturator wire 102 can further be used as the primary punch, especiallyif the distal tip of the obturator wire 102 is sharpened. If theobturator wire 102 is used as the primary punch, the proximal end of theintermediate tube hub is fitted with a Tuohy-Borst or other hemostaticvalve to permit the obturator wire 102 to remain in place. In thisembodiment, sidearms affixed proximal to the proximal end of the punch,and operably connected to the central lumen, serve to permit pressuremonitoring and dye contrast injection without compromising hemostasis orair entry into the punch assembly 400.

FIG. 6 illustrates a side view of an adjustable spacer 600interconnecting a guide catheter 620 and a punch assembly 100. Thespacer 600 further comprises a proximal connector 602, a rotating nut604, an inner telescoping tube 608, a threaded region 606, a distallocking connector 610, and an outer telescoping tube 614. The guidecatheter further comprises a tube 622, a hub 624, and a proximalconnector 626. The punch assembly 100 further comprises the stopcock110, the distal rotating locking connector 612, the intermediate tubepointer 112, the outer tube pointer 114, and the intermediate tube hub116. The spacer 600 can comprise an optional slot 630.

Referring to FIG. 6, the punch assembly 100 is inserted through thecentral lumen of the adjustable spacer 600. The distal end of the punchassembly 100 is then inserted through the central lumen of the guidecatheter 620. The hub 624 of the guide catheter 620 is affixed to theproximal end of the guide catheter tube 622. The distal end of the hub624 comprises a female Luer lock connection, which is bonded to, orintegrally affixed to the hub 624. The hub 624 can further comprise aseal or hemostasis valve such as a Tuohy-Borst fitting. The punch 100hub 116 is terminated at its distal end by a swivel male Luer lockconnector 612. The adjustable spacer 600 comprises an outer telescopingtube 614, shown in partial cutaway view that is terminated at itsproximal end with a female Luer lock 602. The proximal end of the outertelescoping tube 614 has a flange that permits rotational attachment ofthe rotating nut 604, shown in partial cutaway view, so that therotating nut is constrained in position, longitudinally, relative to theouter telescoping tube 614 but is free to rotate. The inner telescopingtube 608 is affixed at its distal end with a swivel male Luer connector610, or equivalent. The proximal end of the inner telescoping tube 608is affixed to, or comprises, the integral threaded region 606. Thethreaded region 606 mates with the internal threads on the rotating nut604. As the rotating nut 604 is rotated, either manually or by anelectromechanical device, it moves forward or backward on the innertelescoping tube 608 and threaded region 606 thus changing the spacebetween the hub 116 of the punch 100 and the proximal end of the hub 624of the guide catheter 620. The system is preferably set for spacing thatpre-sets the amount of needle or stylet travel. In an embodiment, therotating nut 604 comprises a quick release that allows disengagement ofthe inner telescoping tube 608 from the outer telescoping tube 614 sothat collapse is permitted facilitating the tissue punching procedure ofadvancing the punch 100 distally relative to the hub 624. The systemfurther comprises hemostatic valves at some, or all, externalconnections to prevent air leaks into the punch 100. The telescopingtube 608 can be set to disengage from the outer telescoping tube 614 toallow for longitudinal collapse so that the punch 100 can be advanceddistally to provide its tissue punching function. In another embodiment,the spacer 600 comprises the slot 630 that permits the spacer to beremoved sideways off the punch 100. The slot 630 is wide enough to allowthe outer tube 106 to fit through the slot 630 so the spacer 600 can bepulled off, or removed from, the punch 100 prior to the punchingoperation. Thus, the slot 630 can be about 0.048 to 0.060 inches wideand extend the full length of the spacer 600. With the slot 630, thespacer 600 comprises a generally “C-shaped” lateral cross-section. Thespacer 600 can further comprise a slot closure device (not shown) toprevent inadvertent removal of the punch 100.

In another embodiment, the threaded region 606 and the rotating nut 604are replaced by a friction lock on telescoping tubes, a ratchet lock, orother suitable distance locking mechanism. In yet another embodiment, ascale or series of markings (not shown) is incorporated into theadjustable spacer 600 to display the exact distance between the proximalend and the distal end of the spacer 600. In another embodiment, theproximal end and the distal end of the spacer 600 do not comprise one orboth of the female Luer lock 602 or the rotating male Luer lock 610. Inthis embodiment, the spacer 600 provides positional spacing but does notaffix the punch 100 to the guide catheter 620 so that the two devicesmove longitudinally as a unit. In another embodiment, the pull wires 412of FIG. 4, which are strong in tension but cannot support compressionare replaced by one or more control rods, which are flexible but whichhave column strength. Thus, deflection can be generated by impartingeither tension on the control rod or compression and such tension andcompression is capable of deflecting the distal tip of the punch 400without the need of a separate control rod to impart tension in theother direction. The intermediate tube hub 116 is terminated at itsproximal end by a female Luer, Luer lock, threaded adapter, bayonetmount, or other quick release connector. The quick connect or femaleLuer can be releasably affixed to a hemostasis valve, other stopcock,pressure transducer system, “Y” or “T” connector for pressure andradiopaque contrast media infusion, or the like.

In another embodiment, a vacuum line can be connected to a port affixedto the proximal end of the punch. The port can be operably connected toa bell, cone, or other structure at he distal end of the punch by way ofa lumen, such as the central lumen of the intermediate tube or anannulus between the intermediate and outer tube, within the punch. Byapplication of a vacuum at the proximal end of the punch, the distalstructure can be releasably secured to the atrial septum prior topunching through. In another embodiment, a corkscrew structure projectsout the distal end of the punch and is operably connected to a knob orcontrol at the proximal end of the punch by way of a control rodslidably or rotationally free to move within a lumen of the punch. Thecorkscrew structure can be screwed into tissue to releasably secure thedistal end of the punch to the tissue, for example, to enhance stabilityof the punch prior to, during, or after the punching operation.

Referring to FIG. 1, in another embodiment, the intermediate tube 104,the outer tube 106, or both, are fabricated from shape memory nitinol.In this embodiment, electrical energy can be applied to the pre-bentregions of the inner tube 104, the outer tube 106, or both. Uponapplication of electrical energy, Ohmic or resistive heating occurscausing temperature of the tubes to increase. The nitinol changes itsstate from martensitic to austenitic, with the increase in temperature,and can assume a pre-determined configuration or stress state, which isin this case curved. The austenite finish temperature for such aconfiguration is approximately 40 degrees centigrade or just above bodytemperature. In yet another embodiment, the austenitic finishtemperature can be adjusted to be approximately 28 to 32 degreescentigrade. The punch 100 can be maintained at room temperature where itis substantially martensitic and non-rigid. Upon exposure to bodytemperatures when it is inserted into the core lumen of the guidecatheter, it will assume its austenitic shape since body temperature isaround 37 degrees centigrade. This can cause the punch 100 to curve fromsubstantially straight to substantially curved. In this configuration,only a single tube, either the intermediate tube 104 or the outer tube106 is necessary, but both tubes, while potentially beneficial, are notrequired.

The punch can be used to create holes in various structures in the body.It is primarily configured to serve as an articulating or variabledeflection Brockenbrough needle. However, the steerable punch can beused for applications such as transluminal vessel anastomosis, biopsyretrieval, or creation of holes in hollow organs or lumen walls. Thepunch can be used in the cardiovascular system, the pulmonary system,the gastrointestinal system, or any other system comprising tubularlumens, where minimally invasive access is beneficial. The punch can beconfigured to be coring or non-coring in operation, depending on theshape of the distal end and whether an obturator or the circular hollowend of the punch is used to perform the punching operation. In thecoring configuration, a plug of tissue is removed, while in thenon-coring configuration, substantially no tissue is removed from thepatient. The punch facilitates completion of transseptal procedures,simplifies routing of the catheters, minimizes the chance of embolicdebris being dislodged into the patient, and improves the ability of thecardiologist to orient the punch for completion of the procedure. Thepunch of the present invention is integral and steerable. It isconfigured to be used with other catheters that may or may not besteerable, but the punch disclosed herein does not require externalsteerable catheters or catheters with steerability to be steerable as itis steerable or articulating on its own. The punch is capable of bendingand unbending a practically unlimited number of times. The punch isespecially useful with catheters that are not steerable since the punchcomprises its own steering system.

The present invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. For example, the deflecting wires 412 can bereplaced by an electromechanical actuator and external control unit. Thescope of the invention is therefore indicated by the appended claimsrather than the foregoing description. All changes that come within themeaning and range of equivalency of the claims are to be embraced withintheir scope.

I claim:
 1. A transseptal punch system for penetrating the atrial septumof a patient, said system comprising: a guide catheter adapted forinsertion into the right atrium of a patient's heart, said guidecatheter characterized by a distal end, and proximal end, and a guidecatheter lumen extending from the distal end to the proximal end; atransseptal punch, said transseptal punch having a distal end and aproximal end, said transseptal punch fitting within the guide catheterlumen and being longitudinally advanceable within the guide catheter,said punch comprising: an outer tube, said outer tube characterized by adistal end and a proximal end, and an outer tube lumen extending fromthe distal end to the proximal end thereof, said outer tube having aflexible region near the distal end of the outer tube; a control roddisposed within the outer tube, said control characterized by a distalend and a proximal end; wherein the control rod is fixed to the distalend of the outer tube; and an inner tube fixed to the distal end of theouter tube, said inner tube having a sharp point for penetrating theatrial septum of the patient.
 2. The system of claim 1 wherein: thecontrol rod is fixed to the distal end of the outer tube, at a pointdistal to the flexible region.
 3. The system of claim 1 wherein: thecontrol rod is fixed to fixed to the distal end of the outer tube, at apoint distal to the flexible region and off-center relative to the longaxis of the outer tube.